Hi guys. I pushed some libraries I've been working on to git:// repo.or.cz/factor/jcg.git that y'all might find useful:
• svg provides some parsers to help parse out paths and transforms from SVG documents, building on Dan's xml libraries. If you've got an SVG document like this: -- <" <svg xmlns="http://www.w3.org/2000/svg";> <path d="M 10 10 L 630 470" transform="translate(10.0 10.0) rotate(45)" /> </svg> "> string>xml -- You can extract the path tag and tease out its nodes and transform like so: -- body>> children-tags first [ tag-d ] [ tag-transform ] bi -- Which'll give you back an array of path commands and an affine- transform object, respectively. Speaking of which, • math.affine-transforms provides operations for affine transforms of two-dimensional vectors. You could get the same effect with a 3x3 matrix, but it'd be less convenient and efficient. There are words for transforming vectors ( a.v ), combining transforms ( a. ), and inverting transforms ( inverse-transform ), as well as constructors for the common cases of translation, rotation, and scaling transforms. • literals provides syntax for interpolating constant words and expressions into literal values at parse time. For example, you can evaluate √2/2 to build a literal 45º transform using $[ ] : -- USE: literals T{ affine-transform f { $[ 2.0 sqrt 0.5 * ] $[ 2.0 sqrt 0.5 * ] } { $ [ 2.0 sqrt -0.5 * ] $[ 2.0 sqrt 0.5 * ] } { 0.0 0.0 } } -- Or you can define a word for √2/2 and interpolate it using $ : -- USE: literals << : sin-45 ( -- x ) 2.0 sqrt 0.5 * ; >> T{ affine-transform f { $ sin-45 $ sin-45 } { $[ sin-45 neg ] $ sin-45 } { 0.0 0.0 } } -- One caveat is that $ and $[ can't reference words from the same compilation unit, hence the << >> in the example above. In real code you'd want to shoot your constants out to a separate vocab if you're planning on using literals. • sequences.squish is a replacement for the flatten word from sequences.deep that parameterizes the descent predicate. The words in sequences.deep are hard-coded to descend into all sequences except integers and strings. While this is a pretty sane default, sometimes you actually want to descend into strings. squish lets you do that: -- : squish-strings ( seq -- seq' ) [ { [ sequence? ] [ integer? not ] } 1&& ] "" squish ; -- The predicate in that example causes squish to descend all sequences besides integers. -Joe ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Factor-talk mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/factor-talk
